Dryer having bilaterally mounted rolls

ABSTRACT

The invention relates to a dryer having an upper row and a lower row of rolls, the rolls being replaceably arranged in modular manner in the dryer. The invention is characterised in that each roll module comprises a roll having two bearings and having a front and a rear support.

The invention relates to a dryer having an upper row and a lower row of rolls, the rolls being replaceably arranged in modular manner in the dryer.

According to the prior art, contact dryers for drying web-form or thread-form material are known in which an upper row and a lower row of rolls are arranged in such a way that the material being dried passes around each roll at a wrap angle of approximately 180°. The known contact dryers have the advantage of good accessibility in order to enable the web-form or thread-form material to be introduced or to allow access in the event of possible malfunctions. In order that accidents do not occur during operation, the contact dryers must be fully enclosed in a housing. Since, during operation, the surfaces of the rolls are subject to mechanical and/or chemical wear caused by the product, the rolls must be replaced after a certain period of operation in order to rework the surfaces. The known closed housing gives rise to a considerable amount of effort for removal of the rolls, because the covering has in some cases to be entirely demounted. The demounting of the covering can require more effort than the replacement of the rolls. This is associated with long downtimes of the entire system.

The problem of the invention is to provide a contact dryer which enables a quick roll change to be carried out using simple means.

The invention solves that problem by the teaching according to claim 1; further advantageous structural features of the invention are characterised by the subsidiary claims.

In accordance with the technical teaching according to claim 1, the dryer comprises an upper row and a lower row of rolls, the rolls being replaceably arranged in modular manner in the dryer. According to the invention, each roll module comprises a roll having two bearings and having a front and a rear support. Due to the fact that the rolls, together with the bearings, are arranged on the supports, it is possible for the roll module to be removed from the dryer and replaced with very little effort by demounting the supports. Downtimes are considerably reduced, so that the system availability can be significantly increased. The concept of the demountable and replaceable roll module enables the heat loss of the dryer to be significantly reduced, especially if only one roll is defective and needs to be replaced quickly.

In an advantageous arrangement, a lower roll module with its support is releasably attached to the framework of the dryer. The upper roll module, on the other hand, with its support is releasably attached to a stand, the stand creating the spacing between the upper row of rolls and the lower row of rolls and corresponding approximately to a roll diameter, so that the endless web-form material wraps around all the rolls at approximately 180°. The attachment of the lower roll module to the framework and the attachment of the upper roll module to the stand enables the dryer to have a simple construction. On the framework of the dryer, therefore, a stand for an upper roll module and a support for a lower roll module are arranged alternately one next to the other. As a result, there is no need for a lateral framework or a lateral stand that accommodates the bearings for the rolls. Since the stand for the upper roll module is arranged, without a gap, next to a support for the lower roll module and is attached to the framework, a self-stabilising structure is obtained which allows individual roll modules to be demounted or replaced.

A further improvement can be achieved if each roll has, arranged in an end face, at least one opening in which a lifting device of a floor-bound transport vehicle can engage. Unlike an overhead crane, lateral engagement by a floor-bound transport vehicle means that the upper covering of the housing or insulation of the dryer need not be demounted. A further advantage is that the roll modules can be demounted in a horizontal position and withdrawn laterally. This simplifies the positioning during mounting and demounting. At the same time, only a small opening in the covering of the dryer is necessary in order to demount the roll modules.

In an advantageous embodiment, at least one opening is of rectangular construction and is suitable for receiving one or two forks of a fork-lift truck. This is associated with the advantage that the roll module is unable to twist around the lifting device. Mounting is made simpler, because the roll module cannot tilt during insertion. Furthermore, the roll module is secured interlockingly on the forks of the truck so that potential accidents can be avoided.

A further improvement in respect of system availability and energy efficiency is achieved as a result of the dryer having a lateral covering in the region of the end faces of the rolls, which lateral covering consists of a fixedly mounted lower covering for the stands and supports and an upper openable covering. Due to the fact that only the region of the covering in which the roll modules are arranged needs to be opened, the time required for roll changing is reduced, because it is no longer necessary to demount the entire housing of the dryer. Particularly when only one roll has to be changed, the remainder of the covering is able to store significantly more heat than in the case of the prior art.

As regards system availability, it is advantageous that the upper openable covering is vertically movable along one or more guide means. It is thus possible with very little effort for the covering to be opened sufficiently far for the roll modules to be demounted and changed. The vertical movability of the upper covering reduces the amount of space required for the dryer, because according to the prior art the walls or parts of the lateral covering had to be removed and set down.

In an advantageous embodiment, the upper openable covering comprises an uninterrupted covering and a structured covering arranged therebelow. The structured covering can have viewing windows, apertures etc. and is matched to the structural circumstances of the dryer. The uninterrupted covering is constructed so as to be extremely simple and high-quality in terms of its insulating effect, so that the openable covering can be constructed economically.

The structured covering has apertures complementary to the bearings and supports of the roll modules. Due to the fact that the upper openable covering rests on the supports, the demounting of the roll modules can be begun even though the lateral covering is still closed. The heat loss of the dryer is minimised and at the same time the system availability is increased.

The invention is explained in greater detail below with reference to a possible exemplary embodiment shown diagrammatically in the drawing, wherein:

FIG. 1: is a side view of a closed contact dryer;

FIG. 1 a: shows an upper roll module;

FIG. 1 b: shows a lower roll module;

FIG. 2: is a perspective view of a partly open contact dryer.

FIG. 1 shows a contact dryer 1 in which the rolls W1, W3, W5 and W7 form an upper row of rolls, and the rolls W2, W4, W6 and W8 form a lower row of rolls. A web-form material 2, or alternatively endless threads or filaments, is guided through an inlet opening 3 to the first roll W1 and around that roll to a second roll W2 until it has wrapped around all the rolls and the web-form material 2 is supplied via an outlet opening 4 to a further processing step. The rolls W1-W8 are arranged so that the web-form material 2 wraps around them at approximately 180° and in so doing is dried by the contact with the heated rolls. For that purpose, the upper row of rolls W1, W3, W5, W7 are arranged in vertical alignment staggered by approximately one roll diameter relative to the lower row of rolls W2, W4, W6, W8. All the rolls are mounted in a bearing 5 at each end; in the case of the upper row of rolls W1, W3, W5, W7, the bearings 5 are arranged on supports 6 which are in turn attached to a stand 7. The stand 7 essentially creates the vertical spacing relative to the lower row of rolls. In the lower row, each of the rolls W2, W4, W6, W8 is arranged, together with the bearings 5 at each end, on a respective support 8 which is in turn attached to the framework 9 or base of the contact dryer 1.

The replacement of the upper row of rolls W1, W3, W5, W7 is effected by releasing the supports 6 from the stand 7 on each side. A fork-lift truck can introduce its prongs or forks into at least one opening 10 arranged in the end faces of the rolls W1-W8 and withdraw the entire roll, including bearings 5 and support 6, from the contact dryer 1. A fresh roll is inserted in the reverse sequence.

The replacement of the lower rolls W2, W4, W6, W8 is effected analogously by releasing a screw connection or fastening (not shown) so that the support 8 is released from the framework 9 or base. Here too it is possible to use a fork-lift truck which introduces its fork into the at least one end-face opening 10, above the bearing 5, in the roll W2, W4, W6 or W8 and removes the roll, including the bearings 5 and supports 8 at each end, from the contact dryer 1.

As shown in FIGS. 1 a and 1 b, an upper roll module is formed by an upper roll, a front and a rear support 6, and by two bearings 5, each of which is arranged on a support 6 and supports the upper roll. Analogously, the lower roll module is formed by a lower roll, a front and a rear support 8, and by two bearings 5, each of which is arranged on a support 8 and supports the roll. By virtue of the modular manner of construction, each roll can be quickly changed and replaced by a fresh roll with very little effort.

On the framework 9 or base of the contact dryer 1, therefore, a stand 7 for an upper roll module and a support 8 for a lower roll module are arranged alternately one next to the other. As a result, there is no need for a lateral framework or a lateral stand that accommodates the bearings for the rolls. Since the stand 7 for the upper roll module is arranged, without a gap, next to a support 8 for the lower roll module and is attached to the framework 9, a self-stabilising structure is obtained which allows individual roll modules to be demounted or replaced.

The at least one opening 10 arranged in an end face in the rolls allows simple handling and transport by any desired floor-bound transport vehicle. Since, in large establishments, fork-lift trucks are used as standard for transporting heavy loads, the rectangular shaping of one or more openings 10 enables one or two forks of a fork-lift truck to be introduced into the roll, to lift the latter and to withdraw the entire roll module from the contract dryer 1. The rectangular opening, which is matched to the forks of a fork-lift truck, prevents the roll module from twisting while being lifted and transported. This makes roll-changing safer and also more accurate, since the roll modules can be positioned exactly. If it were desired to replace the rolls using an overhead crane as in accordance with the prior art, complete demounting of the upper and top coverings of the contact dryer would be necessary. The invention therefore makes it possible to carry out a roll change that requires only a portion of the lateral covering of the contact dryer to be opened.

According to FIG. 2, the housing of the contact dryer 1 has been adapted for a quick roll change. In the left-hand region of the contact dryer 1, the entire covering of the contact dryer 1 is shown closed. The rolls W1-W4 are indicated behind the closed covering. The covering or housing of the contact dryer 1 comprises a fixed, non-openable covering, of which a covering 12 can be seen in the region above the end faces of the rolls. The side walls with the inlet and outlet openings 3, 4 are likewise configured so that, although they are demountable with effort, they are not normally openable. Furthermore, the top covering of the contact dryer is also fixedly mounted and not normally openable. Only the upper portion of the covering can be opened without any great effort. An upper covering comprises an uninterrupted covering 13 and, arranged therebelow, a structured covering 14 which is matched to the supports 6, 8 and the bearings 5. The upper covering 13, 14 is vertically movable along one or more guide means 11.

In the right-hand region, the upper covering 13, 14 of the contact dryer 1 has been opened sufficiently far for the rolls W5-W8 to be changed, the uninterrupted covering 13, together with the structured covering 14, having been slid vertically upwards along the guide means 11. Since the covering elements 12, 13, 14 are thermally insulated and so are correspondingly heavy, a mechanical or automatic drive means 17 can raise and secure the movable covering 13, 14. The rolls W5-W8, after the release of fastening elements, can be pulled out of the contact dryer 1 together with the supports 6, 8 and the bearings 5, for example by means of a fork-lift truck introducing its fork into the at least one opening 10 and withdrawing the roll from the contact dryer 1. Once the rolls have been changed, the upper covering 13, 14 is lowered again. The structured covering 14 has apertures 15 complementary to the shape of the bearings 5. The structured covering 14 also has apertures 16 complementary to the supports 6 and to the bearings 5 arranged thereon. The upper covering 13, 14 therefore rests on the supports 6, 8, so that the latter are not concealed. It is therefore possible to begin or prepare for the demounting of the rolls while the housing is still closed, so that a potential loss of heat from the contact dryer 1 can be minimised.

REFERENCE SYMBOLS

-   1 contact dryer -   2 web-form material -   3 inlet opening -   4 outlet opening -   5 bearing -   6 support -   7 stand -   8 support -   9 framework -   10 opening -   11 guide means -   12 covering -   13 uninterrupted covering -   14 structured covering -   15 aperture -   16 aperture -   17 drive means -   W1, 2, 3, 4, 5, 6, 7, 8 rolls 

1. Dryer having an upper row and a lower row of rolls, the rolls being replaceably arranged in modular manner in the dryer, characterised in that each roll module comprises a roll having two bearings and having a front and rear support.
 2. Dryer according to claim 1, characterised in that a lower roll module with its support is releasably attached to the framework of the dryer.
 3. Dryer according to claim 1, characterised in that an upper roll module with its support is releasably attached to a stand.
 4. Dryer according to claim 1, characterised in that each roll has, arranged in an end face, at least one opening in which a lifting device of a floor-bound transport vehicle can engage.
 5. Dryer according to claim 4, characterised in that the at least one opening is of rectangular construction and is suitable for receiving one or two forks of a fork-lift truck.
 6. Dryer according to claim 1, characterised in that the dryer has a lateral covering in the region of the end faces of the rolls, which lateral covering consists of a fixedly mounted covering and an upper openable covering.
 7. Dryer according to claim 6, characterised in that the upper openable covering is vertically movable along one or more guide means.
 8. Dryer according to claim 6, characterised in that the upper openable covering comprises an uninterrupted covering and a structured covering arranged therebelow.
 9. Dryer according to claim 8, characterised in that the structured covering has aperatures complementary to the bearings and supports of the roll modules.
 10. Dryer according to claim 1, characterised in that the upper openable covering rests on the supports.
 11. Dryer according to claim 1, characterised by the use as contact dryer. 